US2376892A

US2376892A - Diaphragm controlled operating unit

Info

Publication number: US2376892A
Application number: US446545A
Authority: US
Inventors: Avigdor Rifat
Original assignee: Individual
Current assignee: Individual
Priority date: 1942-03-14
Filing date: 1942-06-10
Publication date: 1945-05-29
Anticipated expiration: 1962-05-29

Description

May 29, 1945. R. AvlGDOR DIAPHRAGM CONTROLLED OPERATING {JNIT FIG'. "2

Patented May 29, 1945 Rifat Avigdor, Toronto, Ontario, Canada Application June 10, 1942, Serial No. 446,545

Canada March 14, 1942 s claims. '(cl. 137-157) This invention relates toa heat compensating, diaphragm controlled, operating unit for devices operated by fluid pressure.l

Up to the present time many devices'operated by fluid pressure have been produced for use in various fields. A particular problem which is confronted in the manufacture of such devices,

and which is manifest particularly in the. case of instruments, is to provide an instrument which will record with a reasonable degree of accuracy under all conditions. One serious difficulty is presented by constant changes in temperature con- Y ditions which cause expansion and/or contraction of parts of the device. In one particular example, airplane instruments, for instance, temperatures from plus 80 FI to minus 60 F. may be encountered in a short space of time, with the result that due to expansion and/or contraction of parts of the instrument, inaccurate read,- ings result.

A number of attempts have been made to reduce inaccuracies caused by expansion and/or contraction of parts due to temperature change. In some cases in instrument manufacture, bimetallic members have been employed between the instrument mechanism and the diaphragm operating element for reducing the eiects mentioned. Bimetallic helical springs have also been used connecting with the pointer operating shaft of the instrument. However, while various methods of this character have reduced such inaccuracies in some degree, the problem still re#- mains as a serious one. l

I have found that inaccuracies due to expansion and/or contraction of parts caused by change in temperature conditions encountered, can be reduced to a very fine degree at least and in many cases eliminated. It is, therefore, an object of the present invention to produce` means for reducing'to a iine degree, or eliminating, inaccuracies in uid operated devices caused by'expansion and/or contraction of metals due to temperature changes.

A further object of the invention is to provide an extremely simple structure employing a minimun number of parts for accomplishing this resul A still further object of the invention is to provide a means of this character which will 'employ no more parts than are necessary for an instrument of this character and without incor-` porating extra parts for heat compensation.

vWith these and other objects. in view, the invention generally comprises a diaphragm controlled loperating unit comprising a plurallty'of operatively connected elements, at least one of which is a diaphragm, the diaphragm being so formedl as to expand'and/or contract to its greatest degree substantially at right angles to its normal operating plane in response to temperature conditions, at least one of saidelements being expandible and/or contractible to its greatest degree, in a predetermined direction, in response to temperature conditions, whereby expansion and/or contraction of said elements controls the effect on said device when connected with said diaphragm of displacement of the diaphragm and said elements due to temperature conditions.

The structure of the unit may be varied to suit requirements and the parts may be varied in thickness and in material to produce a cooperative combination which will achieve predetermined results to control, oiset or neutralize the eifects caused by vexpansion and/or contraction of the parts. Under the present invention,

it is possible without the addition of extra heat l compensating devices to so choose and arrange the parts that a cooperation between parts of a diaphragm, a diaphragm and its casing, a diaphragm and connecting parts between the casing and the mechanism operated by the diaphragm, etc., to cause the device to react in a predeter-` mined manner to temperature conditions. This may be done in many cases when using similar materials and in other cases by the use of dilervent materials having a different rate of expansion and/or contraction.

The invention will be clearly understood by reference to the following detailed specification taken in conjunction with the accompanying drawings.

In the drawings-"- I Fig. 1 is a transverse section showing a unit' according to the vpresent invention illustrating said unit in cross-section and in relation to other parts of the construction with which it is associated.

Fig. 2 is a topq plan view of the unit ill in Fig. 1. i.

Fig. 3 is a bottom plan Viewv of said unit.`

trated Fig. 4 is a transverse sectio'n taken throughl `1 to 3, Aindicates a diaphragm'controlled operating unit for devices operated by uid pressure which in the form illustrated includes two plateiike members I0 and IIso formed that their 'peripheraledges I2 and I3 and/or portions thereof adjacent the peripheraledges may clamp therebetween a diaphragm VB. The plate-like members otherwise are spaced apart from one another so as to form on each side of the diaphragm the chambers I4 and I5. The plate-like members IIl! andV II are held in airtight engagement with the vperipheral edges of the diaphragm -by means of a ring-like member I6 which is forced onto their peripheral edges under pressure so as nally to which theV diaphragm may be operatively connected to parts of an instrument or the like which .it is designed to operate. This member ispreferably formed with the upper and lower .integral clamping elements I9 and 20 which overlap the inner/peripheral edge ZI of the diaphragm and are forced thereover'into` an airtight engagement therewith. Thus, by employing vsuch a form of connection between the plates II and the diaphragm and the connecting member I6 to connect the plate-like members I0 andl II at their peripheries, clamp the diaphragm B, a varied and wide choice,of material may be made with respect t0 the material of the diaphragm and the material of the enclosing casing. Moreover, substantial variations may be made with respect to the sizeand thickness of Lthese parts.

In the form of construction 'at present referred pansion ofthe diaphragm B, the eiects of the expansion of the latter on the operating mchanism connected with the diaphragm through thev post I8 may be directly control1e,d.` In` other Words, since the plate-like-members It and II firmly grip the peripheral edge of the diaphragm B, radial expansion of such members i@ and II at a given rate 4will oiset the expansion of diaphragm B by effecting a linear stretching or linear counter-expansion of such diaphragm to any chosen degree. Accordingly, the movement of the post I8 in the direction of its axis, to operate'the mechanism with which it is operatively connected, may be controlled to impart, to the mechanism, that degree of movement which is desired and either exclude or directly control any movement thereof caused by expansion and/or contraction of the diaphragm due to temperature conditions.

b. Controlof the movement of the post i8 caused by the effects of expansion and/or contraction of the diaphragm B by temperature conditions may beeiected in the manner described or in conjunction with the supporting structure such as the posts 22 .or may be controlled directly between the supporting structure such as the posts 2'2 and the diaphragm. vIn this connection, by so choosing the supporting structure such that it `wi-ll expand and/or contract as a result of temperature conditions to itsgreatest degree in 'al l -given direction, the result of such expansion and/ or contraction when co-related to the expansion and/or contraction of the diaphragm B may be employed to control the effects of such abnor- I mal expansion and/or contraction of the diaphragm on the mechanism operated thereby. For

' instance, by directing the mass of the material of to, the plate-like member .lis designed to carryv a plurality of posts 22, being formed for instance,

with suitab1e bosses z3 and apertures 24 through' which the posts may be secured. These posts are designed to support, as illustrated, a mechanism formed with the oriiice lla provided with the mounting member I Ib, it is preferred to project a portion of the latter within thisorice and force the posts 22 so that they will expand and/or contract axially to their greatest degree at a given rate, and co-relatin'g this expansion and/or contraction of the diaphragm B, the axialexpansion .of the posts 22 is immediately co-related to that axial 'movement of the post I8 caused by eXpansion and/or contraction of the diaphragm B. Therefore, the effects of such abnormal movement of the post I8 may be directly controlled in it into 'air sealing engagement with the inner periphery of this plate-like member surrounding such orice.

By so choosing the materialsl and/or size and construction for the diaphragm B, plate-like members I0 and I-l ,1 and/or the posts 22, I am able` relation to the results desired from the mechanism operated thereby.

The control of expansion and/or contraction of the diaphragm as above referred to may be carried-out by a choice of materials having diierent coeiiicients of expansion or may be controlled by variation of the mass of material in question.

Thus, the diaphragm yand the casing or plateto control the effect on the device, or displacef lment of the diaphragm and elements of thel con` struction due to temperature conditions so'that in the case of an instrument, for instance, no vinaccuracies in the reading will result due to any displacement of the parts by temperature causes or through which ,a given' displacement 'may be provided for where this `might be desirable.

In-the form vof construction being dealt with,

the diaphragm B is of such character that it willI expand and/or contract as a result of -tempera' f' 1 .ture conditions in 'a' plane substantially at right` 'Y angles to its normal operating plane.

like .members I0 and II are of' such area and 'I'he platelike members I 0 and II may be chosenof the L same material and of the same or similar thickness or of the same material of different thicknesses.` On the other hand, vthese .parts may be cho'sen of materials which are dilerentfrom one another and of the same or similar thickness or of diierent thicknesses. In this waytherefore, a minute control may be obtained ofthe effect of the movement of the diaphragm due to tempera- A ture conditions. Moreover, such control, it will be thickness 'that they will expand an'd/or contract,

as a result of temperature conditions, radially of y YYtheir centers... Thus, by controlling the rate of expansion of the plate-like members `III and Il and co-relating such expansion tothat of the exclear, may be effected with or without rthe use of the supporting posts 22 or other mounting structure or may be caused as a combination between the diaphragm andV the supporting structure contraction of a diaphragm element as a result alone. o v

The control of the .effects of expansion and/or of temperature conditions may be achieved following the plinciples of the present linventionin The application different types of structures. of the principle ofthe presentinvention to capsule type diaphragm units and multiple diaphragm unitsy is illustratedin Figs. 4 and 5. Dealing first with Fig. 4 wherein a capsule type diaphragm unit is disclosed, the

diaphragm elements

25 and 26 may be connected together, and preferably are, by means of a ring-like member 2i forced into Vengagementtherewith and may also be provided with a stiffening plate 28 and a similar plate 29, both forced into engagement with the

elements

25 and 26 respectively. The diaphragm element 25 may be formed of Lone material and the element 25 of another, each having a. coeicient of expansion different from the otherD and co-related in such a manner, that the effects of expansion land/or contraction of these diaphragm elements due to heat conditions, may control the resulting effect on the mechanism of the instrument connected through the post 30. choosing

theelements

25 and 26 so that one may be thicker than the other and not necessarily /of a different material, the eiects of expansion and/or contraction as above referred to may be controlled. l

By employing the'ring-like member 27E as a means of securing the diaphragm elements together and, in the case where these elements, are of a dii'erent material, any electrolytic action l which might be set up between the elements,

andl lthus render the combination impractical for use in some iields, may be eliminated by interposing between the clamped surfaces of the elements a suitable dielectric. Consequently, it will be readily appreciated that the invention has a wide application and is operable under varied conditions.

lThe far reaching effect ofthe invention may be further illustrated by reference to Fig. showing a multiple capsule type diaphragm unit. This structure includes the

diaphragm elements

3i, 32, 33 and 36. that by constructing the unit in suchV a way as to vary and co-relate the materials ofV these four sule and clamp therebetween the circumferential flange ofthe capsule, the plate-like members ner. Alternatively, by co-relating the expansion vthe supporting structure between the unit and On the other hand,4 by

It will be readily appreciated being secured together by means of a ring-like` f member 35a, forced into pressure engagement therewith and in effect forming an airtight seal is formed with a projection 38 which is a continuation of a plate or the like enclosing thebottomelement of the capsule andA corresponding 1 to plate 29 as shown in Fig. 4. Through this con-* struction, the full effects of .the diaphragm unit or capsule are obtained, whereas in addition the f' benets of a casing 'such as describedv in Figs.

. 1 tov 3 are also obtained.

the mechanism operated thereby, the abnormal effects of expansion and/or contraction of the diaphragm by temperature causes is controlled in a simple manner. .As a result, therefore, it will be clear that by vsc choosing and constructing normal operating parts of such a mechanism so as to co-relate the expansion and/or contraction of such parts in vquestion to the eirpansion and/or contraction of a, diaphragm element caused `by temperature conditions, the resulting eect of the latter may be minutely controlled and such control may be a neutralizing of the effects so caused or the use of such effects in some degree where this is desirable.

.While, through the use of the principle outlined in the foregoing specification, it is possible to control the effect of expansion and/or contraction of'the diaphragm due to temperature causes, it will, of course, be apparent that the invention will compensate for minute variations in the physical characteristics of the material. Itis a well established and obvious fact that the value of Youngs.'modulus of elasticitsl varies with the state or condition of the material in relationto temperature and other causes.,

The invention, therefore, lmust compensate for minute variations in thel physical characteristics of the material used, effected through ltem- .perature or other causes. 1

mined properties of ,thermal expansibility and contractibility whereby its maximum expansion and contraction is in a direction substantially at 'right angles to the principal plane of the diaphragm, means for transmitting movement from the diaphragm to said device, and thermal responsive supporting means for said device in spaced position around said movement transmitting means and operatively connected to said diaphragm and having properties of thermal expansibility and contractibility predeterminedly correlated to those of said diaphragm sol as to "Ihus, by providing a combination such that expansion and/or contraction of the diaphragm due to temperature conditions-is counteracted or controlled by a linear stretching ofthe diaphragm in a desired degree, ,depending upon the extent of control desired, the present invention meets this problem in a very simple mancontrol the effective extent of transmitted movelment from vsaid diaphragm to said device due to temperature changes, said supporting means havinga coefiicient of expansion different from that of said diaphragm.

2. A heat compensating, diaphragm controlled operating unit for a uid pressure operated device, ,comprising a diaphragm having predetervmined properties of thermal expansibility'- and contractibility whereby its maximum expansion and, contraction isl in a. direction substantially at 'right angles to the principal plane' of the dlaphragm, means for transmitting movement from the diaphragm to said device; and thermal iesponsive` supporting means for said device-in spaced position around said movement transmit-4 ting means and operatively connectedto said diaphragm and having propertiesof thermal expanoperating unit for a iiuid pressure operated de. vice, lcomprising a diaphragm having predeter-` mined properties of thermal expansibility and contractibility whereby its maximum expansion and contraction is in a, direction substantially at right angles to the principal plane of the diag, phragm, means for transmitting movement from the diaphragm to said device, and a diaphragm casing substantially ,encompassing said diaphragm and being in peripheral clamping engagement therewith and having properties of thermal expansibilityc and contractibility predeterminedly correlated to those of said diaphragm as to control the effective. extent of transmitted movement from said diaphragm to said device due to tem-v perature changes, said diaphragm casing having a coefficient of expansion different from that of said diaphragm and being thermally expandible and contractible in a predetermined direction dif- K ferent from that of said diaphragm.

4. A heat lcompensating, diaphragm controlled operating unit for a iiuid pressure operated vdevice, comprising a diaphragm having `predetermined properties of thermal expansibility and contractibility whereby its'maximum expansion and contraction is in a direction substantially at right angles to the prinipal plane ofv the dia--` phragm, means for transmitting movement from the diaphragm to said device, a diaphragm casing substantially encompassing said diaphragm and being in peripheral clamping engagement therewith, and a super-structure on said casing and interconnecting thelatter and saidY device, said Vsuper-structure having properties of thermal expansibility and contractibility predeterminedly correlated to those of said diaphragm as to control the effective extent of transmitted movement from said diaphragm to said device due to temperature changes, said super'estructure having a coemcient of expansion different from that of said diaphragm.

5. A heat compensating, diaphragm controlled operating unit for a device operated by fluid pressure comprising a casing, a diaphragm disposed Within lthecasing and secured around its periph-- ery in airtight engagement with said casing, supporting means on said casing designed to support mechanism for operative connection with the diaphragm, said casing being formed from a metal having a higher coeilicient of expansion ythan the diaphragm and of an area and thickness to cause expansion and contraction of greatest degree inrdirections radially of its center in re-v sponse to heat conditions encountered, said diaphragm being so formed as to expand and contract to its greatest degree substantially at right angles to its principal plane in response to heat conditions encountered, whereby said fcasing causes linear expansion and contraction of said diaphragm in responsey to heat conditions, said supporting means on the casing possessing such thermal properties as to expand and contract to its greatest degree in a predetermined direction responsive to heat conditions, and being of a metal having a predetermined coeflcient of ex- -pansion, the properties of thermal expansibility and contractibility of the casingl and supporting means being predeterminedly correlated to those of the diaphragm as to control the eiective extent of transmitted movement from said diaphragm to said device due to temperature changes.

6. A heat compensating, diaphragm controlled operating unit for a fluid pressure operated device, comprising a diaphragm having predeter- `mined properties of thermal expansibility and contractibility, and thermal responsive support- 'ing means for said device in spaced position around said movement transmitting means and operatively connected to said diaphragm and having properties of thermal expansibility and contractibility predeterminedly correlated to those of said diaphragm as to control the eiective extent of transmitted movement from said diaphragm -to said device due to temperature changes.

RiFAT -AVIGDORQ